Microchip Technology CDLL827/TR

Overview

CDLL827 from Central Semiconductor (CDI) is a temperature-compensated, hermetically sealed MELF glass zener diode with nominal zener voltage 5.9–6.5 V, 7.5 mA test current, 15 Ω zener impedance, ±0.001 %/°C temperature coefficient, and 500 mW power rating at +50°C - used for precision voltage reference in analog instrumentation and power supply feedback loops.

For engineers reviewing the CDLL827 datasheet, CDLL827 pinout, CDLL827 application, or CDLL827 equivalent, key selection criteria include its low tempco, tight V_Z tolerance, DO-213AA package compatibility with high-reliability surface-mount assembly, and stable operation across –65°C to +175°C.

Technical Context

The CDLL827 employs metallurgically bonded double-plug construction for enhanced thermal stability and long-term voltage drift control. Its zener impedance of 9 Ω (measured at 7.5 mA with 10% AC superimposition) supports low-noise regulation in feedback networks.

Temperature coefficient is specified as ±0.001 %/°C over –55°C to +100°C, verified per JEDEC Std No. 5, enabling use in environments requiring minimal voltage shift across wide ambient ranges without external compensation.

Key Specifications

Pinout & Package

Package: DO-213AA (MELF, SOD-80, LL34), hermetically sealed glass case with tin/lead lead finish; cathode identified by band; axial coefficient of expansion ≈ +6 ppm/°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar zener reference applications.

Compared with CDLL827, CDLL827A offers optimized impedance at 10 mA bias but lacks MIL qualification, while 1N827UR-1 delivers identical electrical performance with full military certification - making CDLL827 the optimal choice for commercial high-reliability applications balancing cost, performance, and DO-213AA form factor.

Availability

CDLL827 is available at Aetrix Electronics and suitable for precision voltage reference, switching power supply feedback, and aerospace sensor conditioning requiring stable component supply across extended temperature ranges.

Supply support for CDLL827 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Central Semiconductor (CDI) is a U.S.-based manufacturer specializing in discrete semiconductors, including zener, Schottky, and switching diodes, with emphasis on high-reliability and temperature-stable devices.

The CDLL82x series was designed specifically for high-stability voltage reference applications demanding low tempco, hermetic packaging, and operation beyond commercial temperature limits - targeting aerospace, instrumentation, and military electronics.

FAQ

What is the nominal zener voltage range of the CDLL827?

The CDLL827 has a nominal zener voltage range of 5.9 V to 6.5 V, measured at a test current of 7.5 mA. This range reflects manufacturing tolerance and ensures compatibility with standard 6.2 V reference designs. The CDLL827 achieves this specification using temperature-compensated double-plug construction to minimize drift across operating conditions.

What package type does the CDLL827 use, and why is it significant?

The CDLL827 uses the DO-213AA (MELF) hermetically sealed glass package. This package provides superior moisture resistance, long-term parameter stability, and thermal expansion matching for high-reliability PCB assemblies. Its axial symmetry and glass-metal seal make the CDLL827 suitable for applications where environmental robustness is critical, such as downhole or aerospace systems.

How does the temperature coefficient of the CDLL827 compare to standard zener diodes?

The CDLL827 features a temperature coefficient of ±0.001 %/°C over –55°C to +100°C - up to 10× tighter than typical 5.6 V zeners (±0.01 %/°C). This ultra-low tempco is achieved through proprietary metallurgical bonding and JEDEC-standardized characterization. In practice, the CDLL827 contributes less than ±0.62 mV drift over a 100°C span in a 6.2 V reference circuit.

Can the CDLL827 replace the CDLL827A in an existing design?

Yes, the CDLL827 can generally replace the CDLL827A, as both share identical V_Z range, tempco, and package. However, the CDLL827A is characterized at 10 mA test current (vs. 7.5 mA for CDLL827), yielding slightly different Z_ZT behavior near operating points. Verify regulation stability at the actual bias current in your CDLL827 implementation before substitution.

What is the maximum power dissipation rating for the CDLL827, and how does it derate with temperature?

The CDLL827 is rated for 500 mW at +50°C ambient, with linear derating of 4 mW/°C above that temperature - reaching zero dissipation at +175°C. This derating curve is defined in Figure 2 of the datasheet and ensures safe operation in high-temperature enclosures. The CDLL827's DO-213AA package supports this rating via efficient axial heat conduction along the leads.